The Q & A on those actually says:
Q: I want to get this for use in the office. I hear everything from birds, keyboarding to footsteps. Earplugs are a pain. Would you recommend a pair?
A: Nope - They are designed to cut out noise at higher levels. Solid earplugs are best to cut out noise from birds, footsteps, keyboards (even loud breathing). With these earmuffs you will likely still hear these "quiet sounds". Now if you are around leaf blowers, lawn tractors, heavy machinery, .50 caliber guns, or the like you will be happy with the comfort level that these muffs provide!